3. If they are taking over-the-counter medications, any herbal or dietary supplement (including Benadryl, Sudafed, St. John's wort, herbal teas, vitamins and garlic supplements) that cannot be stopped for the study duration. Use of over-the-counter drugs for the treatment of minor, short-lived (2 to 3 days) symptoms may be allowable (such as Tylenol) but must first be approved by a study investigator.